#pragma once
#include "../server.hpp"
#include <fstream>
#include <sys/stat.h>
#include <regex>

#define DEFALT_TIMEOUT 30

std::unordered_map<int, std::string> _statu_msg = {
    {100,  "Continue"},
    {101,  "Switching Protocol"},
    {102,  "Processing"},
    {103,  "Early Hints"},
    {200,  "OK"},
    {201,  "Created"},
    {202,  "Accepted"},
    {203,  "Non-Authoritative Information"},
    {204,  "No Content"},
    {205,  "Reset Content"},
    {206,  "Partial Content"},
    {207,  "Multi-Status"},
    {208,  "Already Reported"},
    {226,  "IM Used"},
    {300,  "Multiple Choice"},
    {301,  "Moved Permanently"},
    {302,  "Found"},
    {303,  "See Other"},
    {304,  "Not Modified"},
    {305,  "Use Proxy"},
    {306,  "unused"},
    {307,  "Temporary Redirect"},
    {308,  "Permanent Redirect"},
    {400,  "Bad Request"},
    {401,  "Unauthorized"},
    {402,  "Payment Required"},
    {403,  "Forbidden"},
    {404,  "Not Found"},
    {405,  "Method Not Allowed"},
    {406,  "Not Acceptable"},
    {407,  "Proxy Authentication Required"},
    {408,  "Request Timeout"},
    {409,  "Conflict"},
    {410,  "Gone"},
    {411,  "Length Required"},
    {412,  "Precondition Failed"},
    {413,  "Payload Too Large"},
    {414,  "URI Too Long"},
    {415,  "Unsupported Media Type"},
    {416,  "Range Not Satisfiable"},
    {417,  "Expectation Failed"},
    {418,  "I'm a teapot"},
    {421,  "Misdirected Request"},
    {422,  "Unprocessable Entity"},
    {423,  "Locked"},
    {424,  "Failed Dependency"},
    {425,  "Too Early"},
    {426,  "Upgrade Required"},
    {428,  "Precondition Required"},
    {429,  "Too Many Requests"},
    {431,  "Request Header Fields Too Large"},
    {451,  "Unavailable For Legal Reasons"},
    {501,  "Not Implemented"},
    {502,  "Bad Gateway"},
    {503,  "Service Unavailable"},
    {504,  "Gateway Timeout"},
    {505,  "HTTP Version Not Supported"},
    {506,  "Variant Also Negotiates"},
    {507,  "Insufficient Storage"},
    {508,  "Loop Detected"},
    {510,  "Not Extended"},
    {511,  "Network Authentication Required"}
};

std::unordered_map<std::string, std::string> _mime_msg = {
    {".aac",        "audio/aac"},
    {".abw",        "application/x-abiword"},
    {".arc",        "application/x-freearc"},
    {".avi",        "video/x-msvideo"},
    {".azw",        "application/vnd.amazon.ebook"},
    {".bin",        "application/octet-stream"},
    {".bmp",        "image/bmp"},
    {".bz",         "application/x-bzip"},
    {".bz2",        "application/x-bzip2"},
    {".csh",        "application/x-csh"},
    {".css",        "text/css"},
    {".csv",        "text/csv"},
    {".doc",        "application/msword"},
    {".docx",       "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
    {".eot",        "application/vnd.ms-fontobject"},
    {".epub",       "application/epub+zip"},
    {".gif",        "image/gif"},
    {".htm",        "text/html"},
    {".html",       "text/html"},
    {".ico",        "image/vnd.microsoft.icon"},
    {".ics",        "text/calendar"},
    {".jar",        "application/java-archive"},
    {".jpeg",       "image/jpeg"},
    {".jpg",        "image/jpeg"},
    {".js",         "text/javascript"},
    {".json",       "application/json"},
    {".jsonld",     "application/ld+json"},
    {".mid",        "audio/midi"},
    {".midi",       "audio/x-midi"},
    {".mjs",        "text/javascript"},
    {".mp3",        "audio/mpeg"},
    {".mpeg",       "video/mpeg"},
    {".mpkg",       "application/vnd.apple.installer+xml"},
    {".odp",        "application/vnd.oasis.opendocument.presentation"},
    {".ods",        "application/vnd.oasis.opendocument.spreadsheet"},
    {".odt",        "application/vnd.oasis.opendocument.text"},
    {".oga",        "audio/ogg"},
    {".ogv",        "video/ogg"},
    {".ogx",        "application/ogg"},
    {".otf",        "font/otf"},
    {".png",        "image/png"},
    {".pdf",        "application/pdf"},
    {".ppt",        "application/vnd.ms-powerpoint"},
    {".pptx",       "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
    {".rar",        "application/x-rar-compressed"},
    {".rtf",        "application/rtf"},
    {".sh",         "application/x-sh"},
    {".svg",        "image/svg+xml"},
    {".swf",        "application/x-shockwave-flash"},
    {".tar",        "application/x-tar"},
    {".tif",        "image/tiff"},
    {".tiff",       "image/tiff"},
    {".ttf",        "font/ttf"},
    {".txt",        "text/plain"},
    {".vsd",        "application/vnd.visio"},
    {".wav",        "audio/wav"},
    {".weba",       "audio/webm"},
    {".webm",       "video/webm"},
    {".webp",       "image/webp"},
    {".woff",       "font/woff"},
    {".woff2",      "font/woff2"},
    {".xhtml",      "application/xhtml+xml"},
    {".xls",        "application/vnd.ms-excel"},
    {".xlsx",       "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
    {".xml",        "application/xml"},
    {".xul",        "application/vnd.mozilla.xul+xml"},
    {".zip",        "application/zip"},
    {".3gp",        "video/3gpp"},
    {".3g2",        "video/3gpp2"},
    {".7z",         "application/x-7z-compressed"}
};

class Util
{
public:
    // 字符串分割函数,将src字符串按照sep字符进行分割,得到的各个字串放到arry中,最终返回字串的数量
    static size_t Split(const std::string& src, const std::string& sep, std::vector<std::string>* arry)
    {
        size_t offset = 0;
        // abc,bcd,def
        while (offset < src.size())   // 这里没有等于,因为数组下标比数组大小 小1
        {
            size_t pos = src.find(sep, offset); // 在src字符串偏移量offset处,开始向后查找sep字符,返回找到的位置
            if (pos == std::string::npos)  // 没有找到
            {
                if (pos == src.size())  break;
                arry->push_back(src.substr(offset)); // 把剩余的部分当作一个字串放入arry中
                return arry->size();
            }
            if (pos == offset)  // 查找到的位置等于当前位置,当前字串为空,长度为0
            {
                offset = pos + sep.size();
                continue; // 当前字串是一个空的,没有内容
            }
            arry->push_back(src.substr(offset, pos - offset));
            offset = pos + sep.size();
        }
        return arry->size();
    }

    // 读取文件的所有内容,将读取的内容放入buffer中
    static bool ReadFile(const std::string& filename, std::string* buf)
    {
        std::ifstream ifs(filename, std::ios::binary);
        if (ifs.is_open() == false)
        {
            printf("open %s file failed!", filename.c_str());
            return false;
        }
        size_t fsize = 0;
        ifs.seekg(0, ifs.end); // 跳转读写位置到末尾
        fsize = ifs.tellg();  // 获取当前读写位置相对于起始位置的偏移量,从末尾偏移刚好就是文件大小
        ifs.seekg(0, ifs.beg);  // 跳转到文件起始位置
        
        buf->resize(fsize);  // 开辟文件的空间大小
        ifs.read(&(*buf)[0], fsize);
        if (ifs.good() == false)
        {
            printf("read %s file failed!!", filename.c_str());
            ifs.close();
            return false;
        }
        ifs.close();
        return true;
    }

    // 向文件写入内容
    static bool WriteFile(const std::string& filename, const std::string& buf)
    {
        std::ofstream ofs(filename, std::ios::binary | std::ios::trunc);  // 丢弃原内容
        if (ofs.is_open() == false)
        {
            printf("open %s file failed!", filename.c_str());
            return false;
        }
        ofs.write(buf.c_str(), buf.size());
        if (ofs.good() == false)
        {
            printf("write %s file failed!!", filename.c_str());
            ofs.close();
            return false;
        }
        ofs.close();
        return true;
    }

    // URL编码 -- 避免URL中资源路径与查询字符串中的特殊字符与HTTP请求中特殊字符产生歧义
    // 编码格式: 将特殊字符的ascii值,转换为两个16进制字符,前缀% c++ -> c%2B%2B
    // 不编码的特殊字符: RFC3986文档规定 . - _ ~ 字母, 数字属于绝对不编码字符
    // RFC3986文档规定, 编码格式 %HH
    // W3c标准中规定,查询字符串中的空格,需要编码为+,解码则是+转空格
    static std::string UrlEncode(const std::string url, bool convert_space_to_plus)
    {
        std::string res;
        for (auto& c : url)
        {
            if (c == '.' || c == '-' || c == '_' || c == '~' || isalnum(c))
            {
                res += c;
                continue;
            }
            if (c == ' ' && convert_space_to_plus == true)
            {
                res += '+';
                continue;
            }
            // 剩下的字符都是需要编码成为 %H 格式
            char tmp[4] = {0};
            snprintf(tmp, 4, "%%%02X", c);  // snprintf格式化字符串,和printf一样
            res += tmp;
        }
        return res;
    }

    static char HexToI(char c)
    {
        if (c >= '0' && c <= '9')
            return c -'0';
        else if (c >= 'a' && c <= 'z')
            return c - 'a' + 10;
        else if (c >= 'A' && c <= 'Z')
            return c - 'A' + 10;
        else
            return -1;
    }

    static std::string UrlDecode(const std::string url, bool convert_plus_to_space)
    {
        // 遇到%,则将紧随其后的2个字符,转换为数字,第一个数字左移4位,然后加上第二个数字  + -> 2b %2b->2 << 4 +11
        std::string res;
        for (int i = 0; i < url.size(); i++)
        {
            if (url[i] == '+' && convert_plus_to_space == true)
            {
                res += ' ';
                continue;
            }
            if (url[i] == '%' && (i + 2) < url.size())
            {
                char v1 = HexToI(url[i + 1]);
                char v2 = HexToI(url[i + 2]);
                char v = v1 * 16 + v2;
                res += v;
                i += 2;
                continue;
            }
            res += url[i];
        }
        return res;
    }

    // 响应状态码的描述信息获取
    static std::string StatuDesc(int statu)
    {
        auto it = _statu_msg.find(statu);
        if (it != _statu_msg.end())
            return it->second;
        return "Unknow";
    }

    // 根据文件后缀名获取文件mime
    static std::string ExtMine(const std::string& filename)
    {
        // a.b.txt   先获取文件扩展名
        size_t pos = filename.find_last_of('.');
        if (pos == std::string::npos)
            return "application/octet-stream";
        
        // 根据文件扩展名获取mime
        std::string ext = filename.substr(pos);
        auto it = _mime_msg.find(ext);
        if (it == _mime_msg.end())
            return "application/octet-stream";
        return it->second;
    }

    // 判断一个文件是否是一个目录
    static bool IsDirectory(const std::string& filename)
    {
        struct stat st;
        int ret = stat(filename.c_str(), &st);
        if (ret < 0)
            return false;
        return S_ISDIR(st.st_mode);
    }

    // 判断一个文件是否是一个普通文件
    static bool IsRegular(const std::string& filename)
    {
        struct stat st;
        int ret = stat(filename.c_str(), &st);
        if (ret < 0)
            return false;
        return S_ISREG(st.st_mode);
    }

    // http请求的资源路径有效性判断
    // /index.html -- 前面的/叫做相对根目录  映射是某个服务器上的子目录
    // 想表达的是, 客户端只能请求相对根目录中的资源,其他地方的资源都不予理会
    // /../login -- 这个路径中的..会让路径的查找跑到相对根目录之外,这是不合理的,不安全的
    static bool ValidPath(const std::string& path)
    {
        // 思想: 按照/进行路径分割,根据有多少子目录,计算目录深度,有多少层,深度不能小于0
        std::vector<std::string> subdir;
        Split(path, "/", &subdir);
        int level = 0;

        for (auto& dir : subdir)
        {
            if (dir == "..")
            {
                level--;
                if (level < 0)  // 任意一层走出根目录,都是有问题的
                    return false;
                continue;
            }
            level++;
        }
        return true;
    }
};

class HttpRequest
{
public:
    std::string _method;  // 请求方法
    std::string _path;  // 资源路径
    std::string _version;  // 协议版本
    std::string _body;  // 请求正文
    std::smatch _matches;  // 资源路径的正则提取数据
    std::unordered_map<std::string, std::string> _headers; // 头部字段
    std::unordered_map<std::string, std::string> _params;  // 查询字符串
public:
    HttpRequest() :_version("HTTP/1.1")
    {}

    // 每次处理完请求,需要重置
    void Reset()
    {
        _method.clear();
        _path.clear();
        _version = "HTTP/1.1";
        _body.clear();
        std::smatch match;
        _matches.swap(match);
        _headers.clear();
        _params.clear();
    }

    // 插入头部字段
    void SetHeader(const std::string& key, const std::string& val)
    {
        _headers.insert(std::make_pair(key, val));
    }

    // 判断是否存在指定的头部字段
    bool HasHeader(const std::string& key) const 
    {
        auto it = _headers.find(key);
        if (it == _headers.end())
            return false;
        return true;
    }

    // 获取指定头部字段的值
    std::string GetHeader(const std::string& key) const
    {
        auto it = _headers.find(key);
        if (it == _headers.end())
            return "";
        return it->second;
    }

    // 插入查询字符串
    void SetParam(const std::string& key, const std::string& val)
    {
        _params.insert(std::make_pair(key, val));
    }

    // 判断是否有某个指定的查询字符串
    bool HasParam(const std::string& key) const
    {
        auto it = _params.find(key);
        if (it == _params.end())
            return false;
        return true;
    }

    // 获取指定的查询字符串
    std::string GetParam(const std::string& key) const
    {
        auto it = _params.find(key);
        if (it == _params.end())
            return "";
        return it->second;
    }

    // 获取正文长度
    size_t ContentLength() const
    {
        // Connect-Length: 1234\r\n
        bool ret = HasHeader("Content-Length");
        if (ret == false)
            return 0;
        std::string clen = GetHeader("Content-Length");
        return std::stol(clen);
    }

    // 判断是否是短链接
    bool Close() const
    {
        // 没有Connection字段,或者有Connection但是值是close,则是短链接,否则就是长连接
        if (HasHeader("Connection") == true && GetHeader("Connection") == "keep-alive")
            return false;
        return true;
    }
};

class HttpResponse
{
public:
    int _statu;
    bool _redirect_flag;
    std::string _body;
    std::string _redirect_url;
    std::unordered_map<std::string, std::string> _headers;
public:
    HttpResponse()
        :_redirect_flag(false), _statu(200)
    {}

    HttpResponse(int statu)
        :_redirect_flag(false), _statu(statu)
    {}

    void ReSet()
    {
        _statu = 200;
        _redirect_flag = false;
        _body.clear();
        _redirect_url.clear();
        _headers.clear();
    }

    // 插入头部字段
    void SetHeader(const std::string& key, const std::string& val)
    {
        _headers.insert(std::make_pair(key, val));
    }

    // 判断是否存在指定的头部字段
    bool HasHeader(const std::string& key)
    {
        auto it = _headers.find(key);
        if (it == _headers.end())
            return false;
        return true;
    }

    // 获取指定头部字段的值
    std::string GetHeader(const std::string& key)
    {
        auto it = _headers.find(key);
        if (it == _headers.end())
            return "";
        return it->second;
    }

    void SetContent(const std::string& body, const std::string& type = "text/html")
    {
        _body = body;
        SetHeader("Content-Type", type);
    }

    void SetRedirect(const std::string& url, int statu = 302)
    {
        _statu = statu;
        _redirect_flag = true;
        _redirect_url = url;
    }
    
    // 判断是否是短链接
    bool Close()
    {
        // 没有Connection字段,或者有Connection但是值是close,则是短链接,否则就是长连接
        if (HasHeader("Connection") == true && GetHeader("Connection") == "keep-alive")
            return false;
        return true;
    }
};

typedef enum
{
    RECV_HTTP_ERROR,
    RECV_HTTP_LINE,
    RECV_HTTP_HEAD,
    RECV_HTTP_BODY,
    RECV_HTTP_OVER
}HttpRecvStatu;

#define MAX_LINE 8192

class HttpContext
{
private:
    int _resp_statu; // 响应状态码
    HttpRecvStatu _recv_statu; // 当前接受及解析的阶段状态
    HttpRequest _request;  // 已经解析得到的请求信息
private:
    bool ParseHttpLine(const std::string& line)
    {
        std::smatch matches;
        std::regex e("(GET|HEAD|POST|PUT|DELETE) ([^?]*)(?:\\?(.*))? (HTTP/1\\.[01])(?:\n|\r\n)?", std::regex::icase);
        bool ret = std::regex_match(line, matches, e);
        if (ret == false)
        {
            _recv_statu = RECV_HTTP_ERROR;
            _resp_statu = 400; // Bad request
            return false;
        }

    /*  0: GET /bitejiuyeke/login?user=xiaoming&pass=123123 HTTP/1.1
        1: GET
        2: /bitejiuyeke/login
        3: user=xiaoming&pass=123123
        4: HTTP/1.1    */

        // 请求路径的获取
        _request._method = matches[1];
        std::transform(_request._method.begin(), _request._method.end(), _request._method.begin(), ::toupper);
        // 资源路径的获取,需要进行url解码操作,但是不需要+转空格
        _request._path = Util::UrlDecode(matches[2], false);   // 进行解码
        // 协议版本的获取
        _request._version = matches[4];
        // 查询字符串的获取与处理
        std::vector<std::string> query_string_arry;
        std::string query_string = matches[3];
        // 查询字符串的格式 key=val&key=val.....,先以 & 进行分割,得到各个字串
        Util::Split(query_string, "&", &query_string_arry);
        // 针对各个字串, 以 = 符号进行分割, 得到key和val, 得到之后也需要进行URL解码
        for (auto& str : query_string_arry)
        {
            size_t pos = str.find("=");
            if (pos == std::string::npos)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 400; // Bad request
                return false;
            }
            std::string key = Util::UrlDecode(str.substr(0, pos), true);
            std::string val = Util::UrlDecode(str.substr(pos + 1), true);  // 进行解码
            _request.SetParam(key, val);
        }
        return true;
    }

    // 接受请求首行
    bool RecvHttpLine(Buffer* buf)
    {
        if (_recv_statu != RECV_HTTP_LINE) return false;
        // 1.获取一行数据
        std::string line = buf->GetLineAndPop();
        // 2.需要考虑的要素: 缓冲区的数据不足一行,获取一行的数据超大
        if (line.size() == 0)
        {
            // 缓冲区中的数据不足一行,则需要判断缓冲区的可读数据,如果很长了都不足一行,这是有问题的
            if (buf->ReadAbleSize() > MAX_LINE)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 414; //  URL TOO LONE
                return false;
            }
            // 缓冲区中数据不足一行,但是也不多,就等等新数据的到来
            return true;
        }

        if (line.size() > MAX_LINE)
        {
            _recv_statu = RECV_HTTP_ERROR;
            _resp_statu = 414; //  URL TOO LONE
            return false;
        }
        bool ret = ParseHttpLine(line);
        if (ret == false)
            return false;
        _recv_statu = RECV_HTTP_HEAD;
        return true;
    }

    bool RecvHttpHead(Buffer* buf)
    {
        if (_recv_statu != RECV_HTTP_HEAD) return false;
        // 1.一行一行的取出数据,直到遇到空行, 头部的格式: key:val\r\n key:val\r\n...
        // 1.获取一行数据
        while (1)
        {
            std::string line = buf->GetLineAndPop();
            // 2.需要考虑的要素: 缓冲区的数据不足一行,获取一行的数据超大
            if (line.size() == 0)
            {
                // 缓冲区中的数据不足一行,则需要判断缓冲区的可读数据,如果很长了都不足一行,这是有问题的
                if (buf->ReadAbleSize() > MAX_LINE)
                {
                    _recv_statu = RECV_HTTP_ERROR;
                    _resp_statu = 414; //  URL TOO LONE
                    return false;
                }
                // 缓冲区中数据不足一行,但是也不多,就等等新数据的到来
                return true;
            }

            if (line.size() > MAX_LINE)
            {
                _recv_statu = RECV_HTTP_ERROR;
                _resp_statu = 414; //  URL TOO LONE
                return false;
            }
            if (line == "\n" || line == "\r\n") break;  // 遇到空行,就代表结束了

            bool ret = ParseHttpHead(line);
            if (ret == false)
                return false;
        }
        _recv_statu = RECV_HTTP_BODY;
        return true;
    }

    bool ParseHttpHead(std::string& line)
    {
        // key:val\r\n key:val\r\n ...
        if (line.back() == '\n') line.pop_back();  // 如果末尾是换行,就去掉换行字符
        if (line.back() == '\r') line.pop_back();  // 如果末尾是回车,就去掉换行字符

        size_t pos = line.find(": ");
        if (pos == std::string::npos)
        {
            _recv_statu = RECV_HTTP_ERROR;
            _resp_statu = 400; // Bad request
            return false;
        }
        
        std::string key = line.substr(0, pos);
        std::string val = line.substr(pos + 2);
        _request.SetHeader(key, val);
        return true;
    }

    bool RecvHttpBody(Buffer* buf)
    {
        if (_recv_statu != RECV_HTTP_BODY) return false;
        // 1.获取正文长度
        size_t content_length = _request.ContentLength();
        if (content_length == 0)
        {
            // 没有正文,则请求接受解析完毕
            _recv_statu = RECV_HTTP_OVER;
            return true;
        }
        // 2.当前已经接受了多少了正文,其实就是往_request._body中放了多少数据  _request._body
        size_t real_len = content_length - _request._body.size();
        // 3.接受正文放到body中,但是也要考虑当前缓冲区中的数据,是否是全部的正文
        //      3.1 缓冲区中数据,包含了当前请求的所有正文,则取出的所需的数据
        if (buf->ReadAbleSize() >= real_len)
        {
            _request._body.append(buf->ReadPosition(), real_len);
            buf->MoveReadOffset(real_len);
            _recv_statu = RECV_HTTP_OVER;
            return true;
        }
        //      3.2 缓冲区中的数据,无法满足当前正文的需要,数据不足,取出数据,然后等待新数据的到来
        _request._body.append(buf->ReadPosition(), buf->ReadAbleSize());
        buf->MoveReadOffset(buf->ReadAbleSize());
        return true;
    }
public:
    HttpContext()
        :_resp_statu(200), _recv_statu(RECV_HTTP_LINE)
    {}

    void Reset()
    {
        _resp_statu = 200;
        _recv_statu = RECV_HTTP_LINE;
        _request.Reset();
    }

    int RespStatu()
    {
        return _resp_statu;
    }
    
    HttpRecvStatu RecvStatu()
    {
        return _recv_statu;
    }

    HttpRequest& Request()
    {
        return _request;
    }

    // 接受并解析Http请求
    void RecvHttpRequest(Buffer* buf)
    {
        // 不同的状态,做不同的事情,但是这里不要break,因为处理完请求后,应该立即处理头部,而不是退出更新数据
        switch(_recv_statu)
        {
        case RECV_HTTP_LINE:
            RecvHttpLine(buf);
        case RECV_HTTP_HEAD:
            RecvHttpHead(buf);
        case RECV_HTTP_BODY:
            RecvHttpBody(buf);
        }
        return ;
    }
};

// HttpServer模块
class HttpServer
{
private:
    using Handler = std::function<void(const HttpRequest&, HttpResponse*)>;
    using Handlers = std::vector<std::pair<std::regex, Handler>>;
    Handlers _get_route;
    Handlers _post_route;
    Handlers _put_route;
    Handlers _delete_route;
    std::string _basedir;  // 静态资源根目录
    TcpServer _server;
private:
    void ErrorHandler(const HttpRequest& req, HttpResponse* rsp)
    {
        // 1.组织一个错误展示页面
        std::string body;
        body += "<html>";
        body += "<head>";
        body += "<meta http-equiv='Content-Type' content='text/html;charset=utf-8'>";
        body += "</head>";
        body += "<body>";
        body += "<h1>";
        body += std::to_string(rsp->_statu);
        body += " ";
        body += Util::StatuDesc(rsp->_statu);
        body += "</h1>";
        body += "</body>";
        body += "</html>";
        // 2.将页面数据,当作响应正文,放入rsp中
        rsp->SetContent(body, "text/html");
    }

    // 将HttpResponse中的要素按照Http协议格式进行组织,发送
    void WriteResponse(const PtrConnection& conn, const HttpRequest& req, HttpResponse& rsp)
    {
        // 1.完善头部字段
        if (req.Close() == true)
            rsp.SetHeader("Connection", "close");
        else 
            rsp.SetHeader("Connection", "keep-alive");
        
        if (rsp._body.empty() == false && rsp.HasHeader("Content-Length") == false)
            rsp.SetHeader("Content-Length", std::to_string(rsp._body.size()));
        if (rsp._body.empty() == false && rsp.HasHeader("Content-Type") == false)
            rsp.SetHeader("Content-Type", "application/octet-stream");
        if (rsp._redirect_flag == true)
            rsp.SetHeader("Location", rsp._redirect_url);
        // 2.将rsp中的要素,按照http协议格式进行组织
        std::stringstream rsp_str;
        rsp_str <<  req._version << " " << std::to_string(rsp._statu) << " " << Util::StatuDesc(rsp._statu) << "\r\n";
        for (auto& head : rsp._headers)
        {
            rsp_str << head.first << ": " << head.second << "\r\n";
        }

        rsp_str << "\r\n";
        rsp_str << rsp._body;
        //3.发送数据
        conn->Send(rsp_str.str().c_str(), rsp_str.str().size());
    }

    // 静态资源判断
    bool IsFileHandler(const HttpRequest& req)
    {
        // 1.必须设置了静态资源根目录
        if (_basedir.empty())
            return false;
        // 2.请求方法,必须是GET / HEAD请求方法
        if (req._method != "GET" && req._method != "HEAD")
            return false;
        // 3.请求的资源路径必须是一个合法的路径
        if (Util::ValidPath(req._path) == false)
            return false;
        // 4.请求的资源必须存在,且是一个普通文件
        // 有一种请求比较特殊  纯粹的相对根目录: /   这种情况后边增加一个 index.html
        // index.html   不要忘了前缀的相对根目录, 也就是将请求路径,转成实际存在的路径
        std::string req_path = _basedir + req._path;  // 避免直接修改请求的资源路径,因此定义一个临时对象
        if (req._path.back() == '/')
            req_path += "index.html";
        if (Util::IsRegular(req_path) == false)
            return false;
        return true;
    }
    
    // 判断静态资源请求 -- 将静态资源文件的数据读取出来,放入rsp的_body中,并设置mime
    void FileHandler(const HttpRequest& req, HttpResponse* rsp)
    {
        std::string req_path = _basedir + req._path;  // 避免直接修改请求的资源路径,因此定义一个临时对象
        if (req._path.back() == '/')
            req_path += "index.html";

        bool ret = Util::ReadFile(req_path, &rsp->_body);
        if (ret == false)
            return ;
        std::string mime = Util::ExtMine(req_path);
        rsp->SetHeader("Content-Type", mime);
        return ;
    }

    // 功能性请求的分类处理
    void Dispather(HttpRequest& req, HttpResponse* rsp, Handlers& handlers)
    {
        // 在对应请求方法的路由表中,查找是否含有对应资源的请求的处理函数, 有则调用,没有则返回404
        // 思路: 路由表中存储的是键值对  --  正则表达式 & 处理函数
        // 使用正则表达式, 对请求的资源路径进行正则匹配,匹配成功就使用对应函数进行处理
        // /numbers/（\d+）    /number/12345
        for (auto& handler : handlers)
        {
            const std::regex& re = handler.first;
            const Handler& functor = handler.second;
            bool ret = std::regex_match(req._path, req._matches, re);
            if (ret == false)
                continue;
            return functor(req, rsp); // 传入请求信息,和空的rsp,执行处理函数
        }
        rsp->_statu = 404;
    }

    void Route(HttpRequest& req, HttpResponse* rsp)
    {
        // 1.对请求进行分辨,是一个静态资源请求,还是一个功能性请求
        //      静态资源请求,则进行静态资源的处理
        //      功能性请求,则需要通过几个请求路由表来确定是否有处理函数
        //      既不是静态资源请求,也没有设置对应的功能性请求处理函数,返回404
        if (IsFileHandler(req) == true)
            return FileHandler(req, rsp);   // 是一个静态资源请求,则进行静态资源请求的处理
        
        if (req._method == "GET" || req._method == "HEAD")
            return Dispather(req, rsp, _get_route);
        else if (req._method == "POST")
            return Dispather(req, rsp, _post_route);
        else if (req._method == "PUT")
            return Dispather(req, rsp, _put_route);
        else if (req._method == "DELETE")
            return Dispather(req, rsp, _delete_route);
        
        rsp->_statu = 405; // not fount
    }

    // 设置上下文
    void OnConnected(const PtrConnection& conn)
    {
        conn->SetContext(HttpContext());
        DBG_LOG("new connection %p", conn.get());
    }

    // 缓冲区数据解析+处理
    void OnMessage(const PtrConnection& conn, Buffer* buffer)
    {
        while (buffer->ReadAbleSize() > 0)
        {
            // 1.获取上下文
            HttpContext* context = conn->GetContext()->get<HttpContext>();
            // 2.通过上下文对缓冲区数据进行解析,得到HttpRequest对象
            // 如果缓冲区的数据解析出错, 就直接回复出错响应
            // 如果解析正常,且请求已经获取完毕,才开始去进行处理
            context->RecvHttpRequest(buffer);
            HttpRequest& req = context->Request();
            HttpResponse rsp(context->RespStatu());
            if (context->RespStatu() >= 400)
            {
                // 进行错误响应,关闭连接
                ErrorHandler(req, &rsp); // 填充一个错误显示页面数据到rsp中
                WriteResponse(conn, req, rsp); // 组织响应发送给客户端
                context->Reset();
                buffer->MoveReadOffset(buffer->ReadAbleSize()); // 出错了就把缓冲区的数据清空
                conn->Shutdown();
                return ;
            }
            if (context->RecvStatu() != RECV_HTTP_OVER)
                return ;  // 当前请求还没有接受完整,则退出,等待新数据到来再重新处理
            // 3.请求路由 + 业务处理
            Route(req, &rsp);
            // 4.对HttpResponse进行组织发送
            WriteResponse(conn, req, rsp);
            // 5.重置上下文
            context->Reset();
            // 6.根据长短连接判断是否关闭连接或者继续处理
            if (rsp.Close() == true)
                conn->Shutdown(); // 短链接则关闭连接
        }
    }
public:
    HttpServer(int port, int timeout = DEFALT_TIMEOUT)
        :_server(port)
    {
        // _server.EnableInactivateRelease(timeout);
        _server.SetConnectedCallback(std::bind(&HttpServer::OnConnected, this, std::placeholders::_1));
        _server.SetMessageCallback(std::bind(&HttpServer::OnMessage, this, std::placeholders::_1, std::placeholders::_2));
    }

    void SetBasedir(const std::string& path)
    {
        assert(Util::IsDirectory(path) == true);
        _basedir = path;
    }

    // 设置或添加,请求(请求的正则表达) 与处理函数的映射关系
    void Get(const std::string& pattern, const Handler& handler)
    {
        _get_route.push_back(std::make_pair(std::regex(pattern), handler));
    }

    void Post(const std::string& pattern, const Handler& handler)
    {
        _post_route.push_back(std::make_pair(std::regex(pattern), handler));
    }

    void Put(const std::string& pattern, const Handler& handler)
    {
        _put_route.push_back(std::make_pair(std::regex(pattern), handler));
    }

    void Delete(const std::string& pattern, const Handler& handler)
    {
        _delete_route.push_back(std::make_pair(std::regex(pattern), handler));
    }

    void SetThreadCount(int count)
    {
        _server.SetThreadCount(count);
    }

    void Listen()
    {
        _server.start();
    }
};
